GB2329619A

GB2329619A - Bicycle front fork with shock absorbing structure

Info

Publication number: GB2329619A
Application number: GB9812526A
Authority: GB
Inventors: Sun Hsu Tzu
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-09-30
Filing date: 1998-06-10
Publication date: 1999-03-31
Also published as: GB9812526D0; ITMI980441U1; FR2768988A3; US5954355A; FR2768988B3; IT244089Y1; CA2239375A1; NL1009303C1

Abstract

The bicycle front fork comprises two upper tubes 21, two lower tubes 22 and two fitting members 30 that connect the upper and lower tubes. The upper tubes have projections 27 that are slidably received in slots 31 in the inner walls of the fitting members. The fitting members have flanges 32, protruding blocks 33 and grooves 34 located between each flange and block. The protruding blocks can be inserted into grooves 29 in ring edges 28 of the lower tubes to enable the lower tubes and the fitting members to be fastened together by C shaped retaining rings 36 that cooperate with the grooves 34. Alternatively the fitting members may have protrusions (40, Figure 10) that can be located in retaining slots (42) in the lower tube walls to eliminate the need for the C shaped retaining rings. Within each lower tube 22 is an elastic element 23 and since the projections 27 of the upper tubes can slide in the slots 31 of the lower tubes the upper tubes are able to slide within the lower tubes to provide the bicycle with a shock-absorbing effect.

Description

SHOCK-ABSORBlNG STRUCTURE OF BICYCLE FRONT FORK The present invention relates generally to a bicycle front fork, and more particularly to a shock-absorbing structure of the bicycle front fork.

As shown in FIG. 1, the upper fork tubes 11 of the conventional bicycle shock-absorbing front fork main body 10 are fitted into the lower fork tubes 12, which are provided with a shaft support rod 13 for pivoting an arm-holding member 15 which has a brake shoe 14 and is capable of being actuated by a brake cable 17. The shaft support rod 13 serves as a fulcrum at the time when the brake shoe 14 is at work. In other words, the shaft support rod 13 is subjected to a backward thrust when the brake shoe 14 is engaged with the wheel rim, as illustrated in FIG.

2. As a result, the upper segments of the lower fork tubes 12 are exerted on by a side thrust and a spin force. In order'to stabilize the lower fork tubes 12, a support frame 18 is provided such that the support frame 18 is fastened with the upper segments of the lower fork tubes 12.

Such a shock-absorbing structure of the bicycle front fork as described above is not cost-effective and is rather timeconsuming in installing the structure.

It is therefore the primary airn of the present invention to provide a cost-effective shock-absorbing structure for the bicycle front fork.

It is another aim of the present invention to provide a shock-absorbing structure which can be easily mounted on the bicycle front fork.

In keeping with the principle of the present invention, the foregoing objectives of the present invention are attained by a shock-absorbing structure, which includes two fork tube each having a projection, two fitting members, and a C-shaped retaining ring, as set forth in Claim 1.

An embodiment of the invention will now be described in detail, by way of example, and with reference to the accompanying drawings in which: FIG. 1 shows a perspective view of a bicycle front fork shock-absorbing structure of the prior art; FIG. 2 shows a schematic view of forces exerting on the shaft support rod of the prior art as shown in FIG. 1; FIG. 3 shows a perspective view of a preferred embodiment of the present invention; FIG. 4 shows an exploded view of the embodiment of FIG. 1; FIG. 5 shows a sectional view of the embodiment of FIG. 1; FIG. 6 shows another sectional view of the embodiment of FIG. 1; FIG. 7 shows a schematic view of a fitting member of the embodiment of FIG. 1; FIG. 8 shows another sectional view of the embodiment of FIG. 1; FIG. 9 shows another exploded view of the embodiment of FIG. 1; and FIG. 10 shows another sectional view of the embodiment of FIG. 1.

As shown in FIGS. 3-6, a bicycle front fork main body 20 of the present invention is provided at the bottom end thereof with two parallel upper fork tubes 21 each having a midsection which is provided with a fitting member 30. The fitting member 30 is engaged with a lower fork tube 22. The lower fork tube 22 is provided therein with an elastic element 23. A shaft support rod 24 is fastened at the upper section of the lower fork tube 22 for fastening pivotally an arm-holding member 26 which has a brake shoe 25. The present invention is characterized in that the upper fork tubes 21 are provided in the midsection thereof with a projection 27, and that the fitting member 30 is provided in the inner wall thereof with a slide slot 3 1 which is longitudinally extended and is corresponding in location to the projection 27, and further that the fitting member 30 is provided with a flange 32, a protruded block 33, and a cross insertion groove 34 located between the flange 32 and the protruded block 33 for locating a C-shaped retaining ring 36. The protruded block 33 is corresponding in location to a groove 29 of the stopping ring edge 28 of the lower fork tube 22.

The bottom of the cross insertion groove 34 of the fitting member 30 is provided with an extension portion 35 connecting the flange 32 and the protruded block 33. The cross insertion groove 34 is corresponding in size and thickness to the C-shaped retaining ring 36. The slide slot 31 has a length greater than the length of the retracted upper fork tube 21, as shown in FIGS. 5 and 6. The protruded block 33 and the extension portion 35 of the fitting member 30 are provided with a rigid stop plate 37 in contact with the edge of the groove 29 of the lower fork tube 22.

A rigid frame plate 38 is located in the slide slot 3 1 for eliminating the locating allowance between the fitting member 30 and the projection 27 of the upper fork tube 21.

The fitting member 30 may be provided in the inner wall thereof with a plurality of recesses 301 for reducing the contact area between the fitting member 30 and the upper fork tube 21.

The fitting member 30 may also be provided in the outer wall thereof with a plurality of allowance slots 302 which are longitudinally oriented to facilitate the engaging of the fitting member 30 with the lower fork tube 22, as shown in FIGS. 7 and 8.

Now referring to FIGS. 9 and 10, the protruded block 33 of the fitting member 30 is replaced by a slot 39. The fitting member 30 is further provided with an insertion protuberance 40 corresponding in location to a retaining slot 42 of a retaining edge 41 of the lower fork tube 22. The insertion protuberance 40 is provided with a retaining edge 43 and a guide edge 44. As a result, the C-shaped retaining ring 36 is eliminated for reducing the cost.

In combination, the fitting member 30 is engaged with the upper fork tube 21 and the lower fork tube 22 such that the slide slot 31 of the fitting member 30 is engaged with the projection 27 of the upper fork tube 21, and that the protruded block 33 of the fitting member 30 is engaged with the groove 29 of the lower fork tube 22, and further that the rigid stop plate 37 of the fitting member 30 presses against the groove 29, and still further that the flange 32 of the fitting member 30 is in contact with the stopping ring edge 28 of the lower fork tube 22. The fitting member 30 is further securely engaged with the lower fork tube 22 by the C-shaped retaining ring 36. The shock-absorbing effect of the upper fork tube 21 is attained by the projection 27 which is capable of sliding in the slide slot 3 1 of the fitting member 30. In addition, the elastic element 23 serves to provide the upper fork tube 21 with the shock-absorbing effect.

The disengagement of the fitting member 30 with the lower fork tube 22 is averted by the insertion protuberance 40 which is engaged securely with the retaining slot 42 of the lower fork tube 22.

The embodiments of the present invention described above are to be deemed in all respects as being merely illustrative and not restrictive. According, the present invention may be embodied in other specific forms without deviating from the spirit thereof. The present invention is therefore to be limited only by the scopes of the following appended claims.

Claims

1. A bicycle front fork comprising: two upper fork tubes; two lower fork tubes; and two fitting members fastened between said upper fork tubes and said lower fork tubes; wherein said upper fork tubes are provided respectively in an outer wall thereof with a projection; wherein said lower fork tubes are provided with a stopping ring edge having a grcove; and wherein said fitting members are provided respectively in an inner wall thereof with a slide slot corresponding in location and dimension to said projection of said upper fork tubes, said fitting members further provided in an outer wall thereof with a protruded block, a flange, and an insertion groove located between said flange and said protruded block for locating a Cshaped retaining ring for fastening said fitting member with said lower fork tube.

2.. A bicycle front fork according to claim 1, wherein said insertion groove of said fitting members is provided with an extension portion connecting said flange and said protruded block of said fitting members.

3. A bicycle front fOrkaccording to claim 2, wherein said protruded block and said extension portion are provided respectively with a stop plate pressing against said groove of said lower fork tubes; and wherein said slide slot of said fitting members is provided in an inner wall thereof with a frame plate for eliminating a locating allowance of said slide slot and said projection of said upper fork tube.

4. A bicycle front fork according to any preceding claim, wherein said fitting members are provided respectively in an inner wall thereof with a plurality of recesses for reducing the contact area between said fitting members and said upper fork tubes; and wherein said fitting members are provided respectively in an outer wall thereof with a plurality of allowance slots to facilitate the engaging of said fitting members with said lower fork tubes.

5. A bicycle front fork as defined according to any preceding claim, wherein said fitting members are provided respectively in an outer wall thereof with a slot in place of said protruded block, and an insertion protuberance which is provided with a retaining edge and a guide edge; and wherein said lower fork tubes are provided respectively with a retaining slot.

6. A bicycle front fork substantially as herein described with reference to Figures 3 to 10 of the accompanying drawings.